Battery isolator "Can I get rid of it"?

[brokemerc]

I have a 1995 Bayliner Capri, 3.0 I/O FS. The boat came from the factory with a trolling motor and two batteries. I have since removed the trolling motor. I am still going to run two batteries but the second will just stand alone with nothing hooked to it unless needed then it'll be swapped out. My question is this isolator, can I get rid of it? It seems if my memory is correct that I have a large orange wire running from my starter to the isolator, then the isolator runs to the alternator and other connectors to each battery. Can I just run the orange wire straight to the alternator from the starter and throw the isolator away? Thanks.. (maybe this should be in the mercruiser section...)

 

[Silvertip]

Re: Battery isolator "Can I get rid of it"?

Leave it there. It will keep the second battery charged and maintain isolation beween the two. If you eliminate the isolator and parallel the two batteries the weaker one will always suck the life out of the better of the two until they are equal.

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

No the back up battery is not going to be connected to anything, it will sit in a battery box until needed and then swapped out with the dead primary if needed.

 

[Silvertip]

Re: Battery isolator "Can I get rid of it"?

So if you eliminate the isolator how will that battery be kept charged? A simple set of jumper cables eliminates the need to disconnect the start battery and replacing it with the other battery that may also be dead.

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

But there is no switch to utilize the second battery anyway. The only thing that was origionally connected to it was the trolling motor, it couldn't be used to run the boat reguardless. Yes it would charge off the alternator but could only be used to run the trolling motor. I'll just throw the back up battery on a charger if needed and do it that way. Right now the only battery connected through the isolator will be the primary running battery which will charge off the alternator with or without the isolator. Sorry if i'm confusing on this..

 

[Silvertip]

Re: Battery isolator "Can I get rid of it"?

A battery switch is not necessary when a set of inexpensive jumper cables does the same thing and allows you either jump the start battery if you need to or actually run the rig if necessary. Why would you go through all the trouble of disconnecting one battery and inserting another when all you need to do is jump it. It makes no sense whatsoever to carry a battery along if you are not going to keep it charged. About the time you need to use it it will be dead and you'll kick yourself for not checking it. It doesn't matter if you actually run anything off of it. I realize it's merely a spare but batteries do self-discharge. Keeping the isolator ensures that battery is up to snuff and will work if you need it. About eight bucks gets you a set of jumper cables. You still haven't provided a good reason for getting rid of the isolator.

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

I understand what your saying, I pull batteries and put them on charge after every use so keeping them charged with the isolator isn't a concern as it will always be fully charged. If my primary battery is dead it will most likely be due to alternator problems so the jumper cable theory wouldn't work. Switching cables from one battery to another would take maybe 30 seconds,, not really a big deal.. So back to the isolator question,,, the wiring diagram doesn't show it so I think mine will come out.

 

[Silvertip]

Re: Battery isolator "Can I get rid of it"?

If you have a functioning charging system, why do you pull the batteries after each use to charge them? If the starting battery dies you said it's probably due to an alternator problem but that's not necessarily true and if it was the cause, that's all the more reason to have the isolator, extra battery, and the jumper cables. All of the accessories are running from the start battery so you could have a discharged battery while anchored. Jumper cables will work very well if the start battery goes dead. That's what they are for and the engine will run just fine that way. The reason the isolator does not show up on the Mercruiser wiring diagram is because it is not part of their electrical system. They didn't install it, the boat manufacturer did as part of the trolling motor installation. It's your boat and you seem intent on removing a perfectly functional and practical piece of equipment so do as you wish.

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

Ok you talked me into it.. The isolator stays.. Now I just have to figure out how it's suppose to hook to the batteries..

 

[Silvertip]

Re: Battery isolator "Can I get rid of it"?

Go to the web site for the manufacturer of the isolator and download the manual.

 

[achris]

Re: Battery isolator "Can I get rid of it"?

One engine, two batteries.... Hmmm, seems like a perfect case to throw away the isolator and fit an OFF-ONE-TWO-BOTH switch.... Best of all worlds... Both batteries can be charged AND you don't need to carry jumper leads, just turn the switch....

Chris............

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

Yup.. Picked up an bat1/bat2/off/both switch from NAPA last night,, now i've got two wiring projects to figure out,, the isolator and the new switch..

 

[achris]

Re: Battery isolator "Can I get rid of it"?

Yup.. Picked up an bat1/bat2/off/both switch from NAPA last night,, now i've got two wiring projects to figure out,, the isolator and the new switch..

Check that the switch is a make-before-break type and forget the isolator, throw it in the bin.... There, one wiring project sorted already....

Switch is wired exactly as is sounds. You'll have 3 heavy terminals on the back. One marked 'BAT1', one marked 'BAT2', and the third marked either 'COMMON' or 'ENGINE' or something like that. If you can't figure that out, I suggest you put down the crayons before someone catches you.

Chris............

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

Ouch,, and that wasn't from a crayon wrapper paper cut.. That sounds almost too easy.. Gotta be a catch.. I have a guage and switch already there to toggle from one battery to the other to check the charge. Thanks for the help..

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

I don't have the switch in front of me, what will it say that dictates that it's a "Make Before Break Type" of switch??

 

[achris]

Re: Battery isolator "Can I get rid of it"?

I don't have the switch in front of me, what will it say that dictates that it's a "Make Before Break Type" of switch??

Check with the supplier... If they don't know, get them to find out... If you have a 'Break before make' and switch it with the engine running, goodnight alternator! Just on the subject of switching while the engine is running... NEVER, EVER switch though the OFF position with the engine running.

If you have a multimeter you can check it yourself.

Chris...................

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

I couldn't imagine switching with the engine running but anything is possible I guess. Doesn't make much sense that you would want a switch that would break before make if that would cause alternator damage,, or is that the way all switches are? I see the switches on Iboats are either with field disconnect or without field disconnect.. Most feature an AFD(Alternator Field Disconnect) Switch that protects your alternator from sending current when the battery switch is off, preventing damage to your alternator.

 

[achris]

Re: Battery isolator "Can I get rid of it"?

That would only apply if the alternator has an external field excitation wire. Most marine alternators don't. They are internally excited. They only have an output wire and their chassis as the -ve.

Most switches are in fact make before break, but double check.

I often switch while the engine's running. Sometimes I just forget to switch to BOTH before I start and will do it when I remember. Sometimes I want to save one battery if I discharge the other, like when I'm staying overnight on the boat and will be running a fridge and the anchor light all night

Chris........

 

[brokemerc]

Re: Battery isolator "Can I get rid of it"?

Ok, I'll call the switch mfg when I get home.. Thanks..

 

[metriccrescentwrench]

Re: Battery isolator "Can I get rid of it"?

Got any plans for that isolator?